The contents disclosed in this section only provide background information about embodiments without constituting prior art.
Portable mobile appliances and home electronic appliances are being continuously developed. In pace with this development, research and development are also being continuously conducted for communication modules installed in such appliances. As a result, such communication modules have enhanced performance.
Communication modules may use a plurality of antennas, to enable communication using the same frequency band or different frequency bands. In particular, a communication module, in which antennas use different frequency bands, to enable dual-band communication, has been developed, and is being widely used.
However, when a plurality of antennas is used, electrical or radio interference may occur among the antennas. As a result, communication performance may be degraded.
In order to reduce such electrical or radio interference among the antennas, a method of increasing the distance between the adjacent antennas, thereby increasing isolation between the antennas, has been proposed. However, this method has a problem in that the spatial efficiency of the associated communication module is degraded.
A method for lowering the radio emissivity of each antenna, thereby reducing interference between antennas, has also been proposed. However, this method has a problem in that the performance of the associated communication module is degraded.
Meanwhile, communication modules may have degraded communication performance due to structures of antennas used therein. For example, when plate-shaped antennas printed on a substrate are used, abrupt degradation of communication performance may occur when the distance between the associated communication module and an external appliance, which is a wireless communication counterpart of the communication module, increases.